This invention relates to a novel thiazinobenzimidazole derivative, more particularly, to a thiazinobenzimidazole derivative represented by the general formula (I): ##STR2## wherein R.sub.1 and R.sub.2 are each a hydrogen atom, alkyl group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms or halogen atom, and X represents a hydroxyl group, arylsulfonyloxy group, azide group, alkylcarbonyloxy group having 1 to 6 carbon atoms, arylcarbonyloxy group, thioether group, alkyloxy group having 1 to 6 carbon atoms, alkenyloxy group, aryloxy group, aralkyloxy group or ##STR3## (R.sub.3 is a hydrogen atom, and R.sub.4 is a hydrogen atom, alkyl group having 1 to 6 carbon atoms, alkyl group having 1 to 2 carbon atoms and substituted by a hydroxyl, alkyl-oxycarbonyl, cyclohexyl furanyl or indolyl group, aryl, aralkyl or phenylamino group which may optionally contain one or more substituent groups; or R.sub.3 and R.sub.4 form together with the adjacent nitrogen atom a 5 to 8 membered ring which may optionally contain one or more additional nitrogen atoms or one or more oxygen atoms and which may also contain one or more substituent groups), and an acid addition salt thereof, as well as a process for the preparation of the same.
Many imidazole derivatives have heretofore been known. The present inventors have carried out various studies on certain thiazinoimidazole derivatives and found that the novel compounds represented by the above formula (I) pertain various effects to circulatory systems, more specifically, coronary vasodilating effect, peripheral vasodilating effect and mild hypotensive effect, resulting in the completion of the present invention.